Artefact of the Month

CONTROLLING LIGHTNING INTERCEPTIONS FROM THE GROUND

November, 2009

During the 1960s, the UK’s ground radar system consisted of a number of Master Radar Stations (MRS) supplemented by radar sites with no control capability. Each of the major Lightning Quick Reaction Alert (QRA) airfields had a dedicated MRS which was required to maintain a Recognised Air Picture (RAP) in its own area of responsibility. The MRS passed the information to the UK Air Defence Operations Centre at RAF High Wycombe. Here, the complete picture, known as the UK Air Defence Ground Environment, was shared with adjacent NATO and other friendly countries.

Each Master Radar Station was equipped with a Type 80 search radar and ‘nodding’ height finder radars. The normal internal configuration of a MRS comprised an underground main operations room with a sunken well containing a plotting table showing the projected radar picture. Around the operations room there were smaller rooms (called cabins), each with their Interception Controller (IC) consoles fed by raw radar data from the surface radar antennas.

The Interception Controllers when controlling BAC Lightning interceptions used standard approach tracks to the target, identified by the number of degrees through which the Lightning would turn to roll out behind the target on the same heading at a range of about two miles. For example, when carrying out a ‘90’ against a subsonic target, the IC would aim to have the fighter approach the target on a heading such that the target would cross the Lightning’s nose at a range of five miles. At this point the turn of 90 degrees would be ordered e.g. ’port 240’ to achieve an Airborne Interception (AI) or a visual contact (VISIDENT).The call ‘Judy’ from the fighter indicated the pilot was able to complete the interception with no further help required. Fighter controllers used a small plastic overlay, marked with angles and ranges (see photograph) to assist them in determining the headings to intercept the target.

The Soviet long-range bombers, mainly the slow Tupolev Tu-95 ‘Bear’ and Myasishchev M-4 ‘Bison’, when intercepted by RAF Lightnings over the North Sea, were mostly on airborne surveillance missions. During interceptions, Tu-95 tail gunners typically kept their twin cannon pointing upwards as a sign of not being hostile. Similarly, NATO rules of engagement for interceptions restricted aircrews from locking onto the Tu-95 with fire control radars.

AN EXAMPLE OF A PLASTIC OVERLAY USED BY LIGHTNING INTERCEPTION CONTROLLERS (gifted to the Museum by the RAF Air Defence Radar Museum, Neatishead) WILL FORM PART OF A NEW DISPLAY TO BE OPENED IN FEBRUARY 2010 IN THE MUSEUM’S MIDDLE HALL.